I have made my version of the original Kenner Millenium Falcon floor piece using the base shape from the the "modified floor board for 1979 Millenium Falcon" by Chadra Fan.
Here is one printed out on my A1 mini in PLA and drilled to fit the POTF version of the Falcon.
Millenium_Falcon_smugglers_hatch.stl | 647.5KB |